I just wanted to add some information here in case it helps. I'm running OMV6 stable on my Helios64 - config below, and note one caveat from the last kernel update:
Kernel 6.1.50-current-rockchip64 (NOTE: Staying on 6.1.36 might be advised, network issues, see below)
Armbian 23.8.1 Bullseye (clean install to Bullseye, sdcard then migrated to emmc)
OMV 6.9.0-1 (Shaitan)
Governor set to 408Mhz to 1800Mhz, schedutil governor (I don't remember why I selected this vs. ondemand, somehow I had the impression that it was better for ARM systems)
4 drives, WD Red 5400, 3x12TB, 1x4TB
I run three drives in a MergerFS pool w/ SnapRaid on a regular run, fourth on a separate share. Offsite backups to Borgbase, run weekly. The NAS gets moderate usage - it holds media files, Proxmox VM backups, and 2 TimeMachine shares.
No other random software or services, just OMV.
My system is stable, no unexpected crashes or issues when running the python stress test above, or my Snapraid syncs.
NOTE on the network issue with this kernel is that the most recent update had the effect of making the 2.5GB network interface (eth1, r8152 driver) unstable. It will run for a while, then randomly disappear. I only use it as a secondary path to my other server, so I was able to work around it fairly easily, but this would be a blocking issue if you relied on that. I had to build a kernel with an earlier version of the r8152 driver on another x86 machine with recent 6.1.x kernels, so I'm thinking it is the same/similar issue, but I haven't rolled back or done any serious troubleshooting yet. If you want to move to the 6.1.x branch, I'd recommend a good backup, and sticking with 6.1.36 for the moment.
EDIT: The issue seems to be the same as this user's, related to Bookworm 23.08.1. I'll try their recommended solution of moving up the r8152 driver and see how it goes. I will also freeze updates for the moment if it works (armbian-config -> System -> Freeze).